Strange electrical problems
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Joined: Aug 2019
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W203 C32 AMG 2001 | W208 CLK320 1999
Strange electrical problems
Hi guys, my c32 has gotten completely nuts. While I was driving my car, a message popped up indicating a brake cable wear. The car went straight into limp mode. I panicked, stopped and turned the car off. When I tried to start it, it didn't want to start anymore. This problem has occured in the past, the previous owner told me about it. In the process of fixing the problem, he found a way of starting the car with a wire. Purple wire on the brown connector in the fuse box to a 40 amp fuse, starts the car. But the car starts in limp mode. He replaced the abs unit and the problem went away. Now the problem is back. I connected the purple wire and the 40 amp fuse and I was able to drive the car home in limp mode. I assumed it was water damage. I parked the car in the garage, let it dry up with the battery unplugged. After a day the car started with the key. The horn, wipers, alarm tweeter, cig lighter... all refused working. The SRS and ESR were sometimes ok and sometimes not. After driving the car around a few days everything slowly started working again. Today the car thought: nah i don't feel like it. And refuses to start with the key. It was parked in the garage so could not have gotten wet.
What are possible causes? Doesn't this sound like an EIS problem? Or does the car go in some kind of safe mode and refuse to start until i fix the brake cable? If I connect all the problems it could be the SAM module. Or maybe wiring?
My friend with an OBD scanner is on vacation, so OBD diagnosing is currently not possible. What is the correct approach of finding the cause of the problem? How do I check the wires? Are there any common weak points?
Thank you!
Dennis
What are possible causes? Doesn't this sound like an EIS problem? Or does the car go in some kind of safe mode and refuse to start until i fix the brake cable? If I connect all the problems it could be the SAM module. Or maybe wiring?
My friend with an OBD scanner is on vacation, so OBD diagnosing is currently not possible. What is the correct approach of finding the cause of the problem? How do I check the wires? Are there any common weak points?
Thank you!
Dennis
Senior Member
Joined: Oct 2014
Posts: 254
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From: Oregon
2006 ML350, 2005 C55, 2004 E55
You might be dealing here with a single problem, caused by a bad relay, a fuse module a short in wiring or you might be dealing with multiple issues with overlapping symptoms. I haven't ran into this problem personally but I would approach it by scanning the codes first, you need a decent code scanner that can read each module on the car. I expect a lot of these computers would say "no communication with x module". The next step is looking at the wiring diagrams. The horn, wipers, alarm tweeter, cig lighter and other components that weren't working are not normally powered on when the key is not in the ignition, there's a relay that switches and supplies power to these items. Identify the relay and replace it with a good known relay.
Also, check your transmission electronic plug, these tend to leak and cause all sort of havoc.
Also, check your transmission electronic plug, these tend to leak and cause all sort of havoc.
Thread Starter
Newbie
Joined: Aug 2019
Posts: 2
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W203 C32 AMG 2001 | W208 CLK320 1999
Thanks for the reply. I have checked all fuses and relays and they seem to be fine. The plug on the transmission could indeed be leaking. It did on my CLK and caused the ASR to fail. The strange thing is that the car does start with a wire. The engine revs and is totally fine. However, I am not able to put it in gear. The screwdriver method works, but when I put it in gear the car jerks. Here is a video of me starting the car .
Tomorrow I will have the car diagnosed and hope to find out whats going on.
